hmkdir: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/hmkdir - from package: hfsutils

You may install the required package with command apt-get install {package}

Error in other languages:
hmkdir: bevel nie gevind nie
hmkdir: comandă negăsită
hmkdir: comando não encontrado
hmkdir: commande introuvable
hmkdir: command not found
hmkdir: käsku ei ole
hmkdir: không tìm thấy lệnh
hmkdir: komanda nerasta
hmkdir: Kommando nicht gefunden.
hmkdir: kommandot finns inte
hmkdir: komut yok
hmkdir: nie znaleziono polecenia
hmkdir: níor aimsíodh an t-ordú
hmkdir: no se encontró la orden
hmkdir: no s'ha trobat l'ordre
hmkdir: opdracht niet gevonden
hmkdir: parancs nem található
hmkdir: perintah tidak ditemukan
hmkdir: príkaz nenájdený
hmkdir: příkaz nenalezen
hmkdir: команда не найдена
hmkdir: командата не е открита
hmkdir: 命令找不到
hmkdir: コマンドが見つかりません